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ORIGINAL ARTICLE  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2020 October;60(10):1342-8

DOI: 10.23736/S0022-4707.20.10945-9

Copyright © 2020 EDIZIONI MINERVA MEDICA

lingua: Inglese

The importance of the verification phase following an incremental exercise to ensure maximum oxygen consumption

Muzaffer COLAKOGLU , Ozgur OZKAYA, Gorkem A. BALCI

Department of Education, Faculty of Sport Sciences, Ege University, Bornova, Turkey



BACKGROUND: The purpose of this study was to analyze cardiac output (Qc), stroke volume (SV), heart rate (HR), and arterio-venous O2 difference (a−vO2diff) responses throughout a graded exercise test (GXT) and verification phase (VP) to examine whether SV decrement during the GXT is a main factor for underestimation of the maximal O2 uptake (V̇O2max), or not.
METHODS: Seven well-trained male cyclists volunteered for this study (V̇O2max: 61.7±6.13 mL∙min−1∙kg−1). Following submaximal tests, participants were asked to perform GXT until exhaustion. Then, multisession verifications were performed on different days using ±3% constant work rates. The highest 30-second mean of V̇O2 was considered as the V̇O2max and corresponding external power as peak power output (PPO). The Qc, SV, HR, and a−vO2diff responses were evaluated at both GXT and VP by nitrous-oxide rebreathing method. After repeated-measures analyses, possible significant differences were investigated by LSD/Wilcoxon.
RESULTS: It was shown that the HR and a−vO2diff reached their potentially highest values at the end of the both GXT and VP (192.9±8.8 vs. 190.7±7.9 bpm; 17.1±1.6 vs. 16.9±1.1%, respectively; P>0.05); however, SV (128.8±11.2 vs. 137.3±11.2 mL; P=0.029) and Qc (24.8±2.02 vs. 26.2±2.71 L·min−1; P=0.046) were lower at GXT when compared to the VP. V̇O2 means were, therefore, higher in VP when compared to the GXT (61.7±6.13 vs. 59.1±6.2 mL∙min−1∙kg−1; P=0.041).
CONCLUSIONS: The GXT provided only a peak V̇O2 but not the V̇O2max. Consequently, the real V̇O2max and PPO could be provided by only VP administrations. This is likely to result from the lower Qc and SV responses observed from a prolonged incremental test protocol when compared to short bouts of constant work rate trials.


KEY WORDS: Exercise; Cardiac output; Stroke volume

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